Magnetic catalyst residues and their influence on the field electron emission characteristics of low temperature grown carbon nanotubes

Lee, Yun Hi; Kim, D. H.; Kim, Dong Hyun; Ju, Byeong Kwon

doi:10.1063/1.2267342

Cited by 12 publications

(6 citation statements)

References 19 publications

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“…Such transient ferromagnetism of carbon readily allows it to couple electromagnetically such that intrinsic and externally, electromagnetically driven spin and charge dynamics within the catalyst couple with the carbon to organize its growth. The ferromagnetism of the CNT intermediary states is consistent with the observed ferromagnetism of the catalysts particles after CNT growth [31] and the high saturation magnetization of Fe, Co and Ni filled CNT [32] are evidence of this ferromagnetism of carbon during the growth. Furthermore other investigators have observed the transient ferromagnetism in the parts for this complex system.…”

Section: Resultssupporting

confidence: 81%

On the dynamical ferromagnetic, quantum Hall, and relativistic effects on the carbon nanotubes nucleation and growth mechanism

Little

Biriş

Lupu

et al. 2008

Journal of Magnetism and Magnetic Materials

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The mechanism of carbon nanotube (CNT) nucleation and growth has been under investigation for 15 years, since the discovery of this most explored material of the 20th century. Prior models have attempted the extension of classical transport mechanisms used to explain the older, bigger, micron-sized filamentous carbon formations. In July 2000, a more thorough, detailed, nonclassical, and relativistic mechanism was formulated considering the detailed dynamics of the electronics of relativistic spin and rehybridization dynamics between the carbon and the catalyst via novel mesoscopic phenomena driven by intrinsic dynamical ferromagnetic fields by spin currents and spin waves of the catalyst for activating catalytically stimulated, synchronized, orchestrated, simultaneous, and coherent hydrocarbon decomposition, adsorption, absorption, transport, electronic subshell rehybridization by spin mechanics, and multi-atomic bond rearrangements for the nucleation and growth of the CNT. In this dynamical magnetic mechanism, quantum Hall effects and relativistic Dirac spin effects of intense many body spin-orbital interactions for novel orbital hybrid dynamics (the Little Effect) were proposed due to the mesoscopic size of the system. The formulation of this dynamical ferromagnetic mechanism naturally led to the first realization and explanation of a physical basis for ferromagnetic nanocarbon. This discovered ferromagnetism of the carbon and the forming CNT intermediates facilitates the coupling of the CNT to the ferrocatalyst for the spin currents and spin waves of the catalyst to organize and synchronize the 12 steps for the nucleation and growth processes of the CNT. Here, this dynamical ferromagnetic mechanism of CNT formation via spin currents and spin waves is proven by imposing both an external static magnetic field via the bore of a strong DC magnet and an external dynamic magnetic field via intense radio frequency electromagnetic radiation for influencing the proposed spin currents and spin waves for the observations of the static magnetic field's hindrance on the CNT formation and the dynamic magnetic field's enhancement and selectivity of CNT nucleation and growth. r

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Section: Resultssupporting

confidence: 81%

On the dynamical ferromagnetic, quantum Hall, and relativistic effects on the carbon nanotubes nucleation and growth mechanism

Little

Biriş

Lupu

et al. 2008

Journal of Magnetism and Magnetic Materials

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“…other experimental studies or the assumed similarity between the properties of CNT and graphite) and the intercept with the vertical axis is not analysed with (3) (see [11]). When adsorbed water molecules [12] or metal atoms bonded within the CNT cap structures are present [13,14], φ 0 may become smaller than the accepted value of 4.5 eV. The calculated values of β then exceed 1.2(2.15 + (h/r) CNT ) 0.9 .…”

Section: F-n and M-g Equationsmentioning

confidence: 91%

Field emission calculations revisited with Murphy and Good theory: a new interpretation of the Fowler–Nordheim plot

Dionne¹,

Coulombe²,

Meunier³

2008

J. Phys. D: Appl. Phys.

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The Murphy and Good (M–G) theory for thermo-field emission [1] was used to calculate the emission current densities over the 300–5000 K temperature range in order to bridge the gap with the simpler zero temperature version of the Fowler–Nordheim (F–N) equation. A comparison between the two sets of data reveals that the F–N equation as it is used in the analysis of F–N plots underestimates the true current density by a factor of 102 for all fields known to produce significant current in the case of carbon nanotubes arrays. We propose a new equation for field emission that is consistent with experimental current densities and that can still provide the field enhancement factor β of field emitter arrays. This equation is obtained over the 300–3000 K temperature range by fitting the temperature and field dependences of JM–G using a f(Ts, Es, ϕ0) function using work function values ϕ0 of 4.5 and 2.6 eV. Our complete parametric equation for the fitted M–G current density is found to apply within a 1% error margin for f(Ts, Es, ϕ0) functions computed for each value of ϕ0 and for Es > 1.2 × 109 V m−1.

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“…However, the fabricating technique involved both self-assembled nanomask and anisotropic plasma etching, which may cause high cost. Carbon nanotubes (CNT) is another promising candidate for fabricating field emitters [11][12][13][14]. Especially, thin-walled FeNifilled CNTs showed much lower turn-on field of 0.30 V/mm (at 10 mA/cm 2 ) [14].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and field emission properties of multi-walled carbon nanotube/silicon nanowire array

Qinke¹,

Wei²,

Wang³

et al. 2010

Journal of Physics and Chemistry of Solids

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Magnetic catalyst residues and their influence on the field electron emission characteristics of low temperature grown carbon nanotubes

Cited by 12 publications

References 19 publications

On the dynamical ferromagnetic, quantum Hall, and relativistic effects on the carbon nanotubes nucleation and growth mechanism

On the dynamical ferromagnetic, quantum Hall, and relativistic effects on the carbon nanotubes nucleation and growth mechanism

Field emission calculations revisited with Murphy and Good theory: a new interpretation of the Fowler–Nordheim plot

Fabrication and field emission properties of multi-walled carbon nanotube/silicon nanowire array

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